Arylation of olefins

ABSTRACT

The present invention relates to a process for the arylation of olefins by reaction of haloaromatics or arylsulfonates with olefins in the presence of a palladium catalyst, a bulky nitrogen base and a dipolar aprotic solvent.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a process for the arylation ofolefins by reaction of haloaromatics or arylsulfonates with olefins inthe presence of a palladium catalyst and a bulky nitrogen base, ifappropriate in a dipolar aprotic solvent.

[0003] 2. Background of the Invention

[0004] Many aryl olefins have great industrial importance as finechemicals, UV absorbers, starting materials for polymers andintermediates for active compounds.

[0005] The preparation of arylolefins is frequently carried out by meansof palladium-catalyzed coupling of iodoaromatics or bromoaromatics, andto a lesser extent chloroaromatics or arylsulfonates, with olefins.Owing to the high price of iodoaromatics and bromoaromatics and thelarge amounts of waste product caused by the high molar masses, theiruse on an industrial scale is disadvantageous. However, the more readilyavailable and therefore more attractive chloroaromatics have acomparatively low reactivity.

[0006] Littke and Fu (J. Am. Chem. Soc. 2001, 123, 6989) describe aprocess in which chloroaromatics are reacted with olefins at roomtemperature using palladium-dibenzylideneacetone ([Pd₂(dba)₃]) andtri-tert-butylphosphine in the presence of dicyclohexylmethylamine indioxane. However, the turnover numbers (TONs) are low and large amountsof palladium catalyst are required for the process described, whichmakes its industrial application uneconomical.

[0007] There was therefore a need to develop a process which makes itpossible for haloaromatics, in particular chloroaromatics, to be coupledwith olefins in an efficient way.

SUMMARY OF THE INVENTION

[0008] We have now found a process for preparing arylolefins, which ischaracterized in that

[0009] aromatic compounds of the general formula (I),

Ar—[X]_(n)  (I),

[0010] where

[0011] n is one or two and

[0012] Ar is a substituted or unsubstituted aromatic radical and

[0013] X are each, independently of one another, chlorine, bromine,iodine or a sulphonate,

[0014] are reacted with olefins which bear at least one hydrogen atom onthe double bond

[0015] in the presence of a palladium catalyst,

[0016] at least one bulky nitrogen base and

[0017] in the presence of a dipolar aprotic solvent.

DETAILED DESCRIPTION OF THE INVENTION

[0018] It may be pointed out at this juncture that any combinations ofpreferred ranges are encompassed by the invention.

[0019] For the purposes of the invention, Ar is, by way of example andpreferably, a carbocyclic aromatic radical having from 6 to 24 frameworkcarbon atoms or a heteroaromatic radical having from 5 to 24 frameworkcarbon atoms in which no, one, two or three framework carbon atom(s) perring, but at least one framework carbon atom in the total molecule, canbe replaced by heteroatoms selected from the group consisting ofnitrogen, sulphur and oxygen. Furthermore, the carbocyclic aromaticradicals or heteroaromatic radicals may be substituted by up to fiveidentical or different substituents per ring selected from the groupconsisting of hydroxy, fluorine, nitro, cyano, free or protected formyl,C₁-C₁₂-alkyl, C₅-C₁₄-aryl, C₆-C₁₅-arylalkyl, —PO—[(C₁-C₈)-alkyl]₂,—PO—[(C₅-C₁₄)-aryl]₂, —PO—[(C₁-C₈)-alkyl)(C₅-C₁₄)-aryl)],tri(C₁-C₈-alkyl)siloxyl and radicals of the general formula (II),

A-B-D-E  (II)

[0020] where, independently of one another,

[0021] A is absent or is a C₁-C₈-alkylene radical and

[0022] B is absent or is oxygen, sulphur or NR¹,

[0023] where R¹ is hydrogen, C₁-C₈-alkyl, C₆-C₁₅-arylalkyl orC₅-C₁₄-aryl and

[0024] D is a carbonyl group and

[0025] E is R², OR², NHR³ or N(R³)₂,

[0026] where R² is C₁-C₈-alkyl, C₆-C₁₅-arylalkyl, C₁-C₈-haloalkyl orC₅-C₁₄ aryl and

[0027] R³ are each, independently of one another, C₁-C₈-alkyl, C₆-C₁₅arylalkyl or C₆-C₁₄-aryl or the moiety N(R³)2 is a cyclic amino radical,

[0028] and radicals of the general formulae (IIIa-e)

A-E  (IIIa)

A-SO₂-E  (IIIb)

A-B-SO₂R²  (IIIc)

A-SO₃W  (IIId)

A-COW  (IIIe)

[0029] where A, B, E and R² are as defined above and W is OH, NH₂, orOM, where M can be an alkali metal ion, half an equivalent of analkaline earth metal ion, an ammonium ion or an organic ammonium ion.

[0030] For the purposes of the invention, alkyl or alkylene or alkoxyare each, independently of one another, a straight-chain, cyclic,branched or unbranched alkyl or alkylene or alkoxy radical which may befurther substituted by C₁-C₄-alkoxy radicals. The same applies to thealkyl part of an arylalkyl radical.

[0031] In all contexts, C₁-C₆-alkyl is preferably methyl, ethyl,n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, cyclohexyl orn-hexyl, C₁-C₈-alkyl may also be, for example, n-heptyl, n-octyl orisooctyl, C₁-C₁₂-alkyl may also be, for example, n-decyl and n-dodecyland C₁-C₂₀-alkyl may also be n-hexadecyl and n-octadecyl.

[0032] In all contexts, C₁-C₄-alkylene is preferably methylene,1,1-ethylene, 1,2-ethylene, 1,1-propylene, 1,2-propylene, 1,3-propylene,1,1-butylene, 1,2-butylene, 2,3-butylene and 1,4-butylene,C₁-C₈-alkylene may also be 1,5pentylene, 1,6-hexylene,1,1-cyclohexylene, 1,4-cyclohexylene, 1,2-cyclohexylene and1,8-octylene.

[0033] In all contexts, C₁-C₄-alkoxy is preferably methoxy, ethoxy,isopropoxy, n-propoxy, n-butoxy and tert-butoxy, C₁-C₈-alkoxy may alsobe cyclohexyloxy.

[0034] The general designation aryl as substituent encompassescarbocyclic radicals and heteroaromatic radicals in which no, one, twoor three framework atoms per ring, but at least one framework atom inthe overall radical, are heteroatoms selected from the group consistingof nitrogen, sulphur and oxygen. C₅-C₁₀-aryl is, by way of example andpreferably, phenyl, pyridyl, o-, m-, or p-tolyl, C₅-C₁₄-aryl may also beanthracenyl.

[0035] The same applies to the aryl part of an arylalkyl radical.C₆-C₁₅-arylalkyl is, by way of example and preferably, benzyl.

[0036] For the purposes of the invention, haloalkyl and fluoroalkyl areeach, independently of one another, a straight-chain, cyclic, branchedor unbranched alkyl radical which may be monosubstituted,polysubstituted or fully substituted by halogen atoms selectedindependently from the group consisting of fluorine, chlorine andbromine or by fluorine.

[0037] In all contexts, C₁-C₈-haloalkyl is, by way of example andpreferably, trifluoromethyl, trichloromethyl, 2,2,2-trifluoroethyl,pentafluoroethyl or nonafluorobutyl, C₁-C₈-fluoroalkyl may betrifluoromethyl, 2,2,2-trifluoroethyl, pentafluoroethyl ornonafluorobutyl.

[0038] Protected formyl is a formyl radical which has been protected byconversion into an aminal, acetal or a mixed aminal-acetal, with theaminals, acetals and mixed aminal-acetals being able to be acyclic orcyclic.

[0039] Protected formyl is, by way of example and preferably, a1,1-(2,5-dioxy)cyclopentylene radical.

[0040] In the process of the invention, preference is given to usingaromatic compounds of the general formula (I) in which

[0041] n=one and

[0042] Ar is a substituted or unsubstituted aromatic radical selectedfrom the group consisting of phenyl, naphthyl, biphenyl, binaphthyl,phenanthrenyl, anthracenyl, fluorenyl, pyridinyl, oxazolyl, thiophenyl,benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl,furanyl, indolyl, pyridazinyl, pyrazinyl, pyrimidinyl, triazolyl andquinolinyl which may also be further substituted by no, one, two orthree radicals per ring which are selected independently from the groupconsisting of

[0043] fluorine, nitro, cyano, di(C₁-C₆-alkyl)amino, formyl,C₁-C₆-alkyl, C₅-C₁₀-aryl, C₁-C₈-fluoroalkyl, C₁-C₈-fluoroalkoxy,C₁-C₈-alkoxy, CO(C₁-C₄-alkyl), COO—(C₁-C₆)-alkyl, —CON(C₁-C₆-alkyl)₂,and

[0044] X is chlorine, bromine, iodine, C₁-C₈-perfluoroalkylsulphonyloxysuch as trifluoromethanesulphonyloxy or nonafluorobutanesulphonyloxy orbenzenesulphonyloxy or tolylsulphonyloxy.

[0045] In the process of the invention, particular preference is givento using aromatic compounds of the general formula (I) in which

[0046] n=one and

[0047] Ar is a phenyl radical which may be further substituted by no,one, two or three radicals selected independently from the groupconsisting of

[0048] fluorine, cyano, C₁-C₄-alkyl, formyl, trifluoromethyl,trifluoromethoxy, acetyl, COO—(C₁-C₆)-alkyl, —CON(C₁-C₆-alkyl)₂ and

[0049] X is chlorine or bromine.

[0050] Very particular preference is given to using4-chlorobenzotrifluoride

[0051] Palladium catalysts used are, by way of example and preferably,palladium complexes.

[0052] Palladium complexes can, for example, be generated from palladiumcompounds and suitable ligands in the reaction solution, or can be usedin the form of previously isolated palladium complexes.

[0053] Isolated palladium complexes suitable for the process of theinvention are, for example, palladium complexes containing phosphoruscompounds such as phosphines, phosphites, phosphonites or mixturesthereof, preferably phosphines, as ligands.

[0054] As palladium complexes which can contain phosphorus compounds asligands, use is made, by way of example and preferably, of complexes ofthe general formula (IV),

[PdL₂An₂]  (IV)

[0055] where

[0056] L is in each case a monophosphorus compound or

[0057] L₂ together represents a diphosphorus compound and

[0058] An is an anion, preferably chloride, bromide, iodide, acetate,propionate, allyl or cyclopentadienyl,

[0059] or complexes of the general formula (IVb)

[PdLn]  (IVb)

[0060] where

[0061] n is 2, 3 or 4 and

[0062] L is in each case a monophosphorus compound or can represent halfan equivalent of a diphosphorus compound.

[0063] Monophosphorus compounds are, by way of example and preferably,compounds of the general formula (Va)

P(E-R⁴)₃  (Va)

[0064] where

[0065] E are each, independently of one another and independently of R⁴,absent or oxygen and the radicals R⁴ are each, independently of oneanother, C₁-C₈-alkyl or unsubstituted phenyl, naphthyl or ferrocenyl orphenyl, naphthyl or ferrocenyl substituted by one, two or three radicalsR⁵, where

[0066] R⁵ is C₁-C₈-alkyl, C₁-C₈-alkoxy, chlorine, fluorine,N(C₁-C₆-alkyl)₂, CO₂—(C₁-C₆-alkyl), —CON(C₁-C₆-alkyl)₂, cyano orCO(C₁-C₆-alkyl).

[0067] Particularly preferred monophosphorus compounds are those of thegeneral formula (Va) in which E is absent and R⁴ are each, independentlyof one another, C₁-C₈-alkyl or unsubstituted phenyl or naphthyl orferrocenyl or phenyl or naphthyl or ferrocenyl substituted by one, twoor three radicals R⁵, where

[0068] R⁵ is C₁-C₈-alkyl, C₁-C₈-alkoxy, chlorine or fluorine.

[0069] Very particular preference is given to monophosphorus compoundsof the general formula (Va) in which E is absent and two or three of theradicals R⁴ are each, independently of one

[0070] another, C₁-C₈-alkyl and no or one radical R⁴ is unsubstitutedphenyl or naphthyl or phenyl or naphthyl substituted by one, two orthree radicals R⁵, where

[0071] R⁵ is C₁-C₈-alkyl, C₁-C₈-alkoxy, chlorine or fluorine.

[0072] Even more preferred monophosphorus compounds aretri(tert-butyl)phosphine, phenyldi(tert-butyl)phosphine andferrocenyldi(tert-butyl)phosphine.

[0073] Diphosphorus compounds can be, by way of example and preferably,compounds of the general formula (Vb),

(R⁶-E)₂P-E-Z-E-P(E-R⁶)₂  (Vb)

[0074] where

[0075] E are each, independently of one another and independently of R⁶and Z, absent or oxygen and

[0076] the radicals R⁶ are each, independently of one another,C₁-C₈-alkyl or phenyl, naphthyl or heteroaryl having from 5 to 12framework carbon atoms which may be unsubstituted or substituted by one,two or three radicals R⁷, where

[0077] R⁷ are selected independently from the group consisting ofC₁-C₈-alkyl, C₁-C₈-alkoxy, fluorine and cyano and Z is an unsubstitutedor substituted radical selected from the group

[0078] consisting of C₁-C₄-alkylene, 1,2-phenylene, 1,3-phenylene,1,2-cyclohexyl, 1,1′-ferrocenyl, 1,2-ferrocenyl, 2,2′-(1,1′-binaphthyl)and 1,1′-biphenyl.

[0079] Preference is given to using complexes which containmonophosphorus compounds as ligands.

[0080] Preferred isolated palladium complexes arebistriphenylphosphinepalladium(II) dichloride,tetrakistriphenylphosphinepalladium(0),bistri-o-tolylphosphinepalladium(0),tricyclohexylphosphinepalladium(0)-diallyl ether complex,bistricyclohexylphosphinepalladium(0).

[0081] In the process of the invention, palladium complexes generated inthe reaction solution from palladium compounds and ligands are preferredas palladium catalysts.

[0082] As palladium compounds, it is possible to use, by way of exampleand preferably, Pd₂(dibenzylideneacetone)₃ or allylpalladium chloride orbromide or compounds of the general formula (VIa),

Pd(Y¹)₂  (VIa)

[0083] where

[0084] y¹ is an anion, preferably chloride, bromide, acetate,propionate, nitrate, methanesulphonate, trifluoromethanesulphonate,acetylacetonate, allyl or cyclopentadienyl,

[0085] or palladium compounds of the general formula (VIb)

Pd(Y²)₂L₂  (VIb)

[0086] where

[0087] y² is an anion, preferably chloride, bromide, acetate,methanesulphonate or trifluoromethanesulphonate,nonafluorobutanesulphonate, tetrafluoroborate or hexafluorophosphate and

[0088] L are each a nitrile, preferably acetonitrile, benzonitrile orbenzyl nitrile, or an olefin, preferably cyclohexene or cyclooctene, or

[0089] L₂ together represents a diolefin, preferably norbornadiene or1,5-cyclooctadiene,

[0090] or palladium compounds of the general formula (VIc)

M₂[Pd(Y³)₄]  (VIc),

[0091] where

[0092] Y³ is a halide, preferably chloride or bromide, and

[0093] M is lithium, sodium, potassium, ammonium or organic ammonium.

[0094] Preferred palladium compounds are palladium(II) acetate,palladium(II) chloride, palladium(II) bromide, palladium(II) propionate,palladium(II) acetylacetonate, lithium, sodium or potassiumtetrachloropalladate, bisbenzonitrilepalladium(II) chloride,bisacetonitrilepalladium(II) chloride,cyclopentadienyl(allyl)palladium(II), and palladiumdibenzylideneacetonecomplexes such as [Pd₂(dba)₃].

[0095] Preference is given to using the phosphorus compounds of thegeneral formulae (Va) and (Vb) as ligands for the generation ofpalladium complexes in the reaction solution, with monophosphoruscompounds of the general formula (Va) being particularly preferred. Theabove-mentioned preferred ranges apply in the same way.

[0096] The molar ratio of phosphorus to palladium in the reactionmixture can be, for example, from 1:1 to 100:1, preferably from 2:1 to15:1, particularly preferably from 2:1 to 10:1.

[0097] In the process of the invention, the molar ratio of X to bereplaced in compounds of the general formula (I) to palladium can be,for example, from 10 to 20 000; preference is given to a ratio of from100 to 5 000, very particularly preferably from 500 to 2 000.

[0098] The process of the invention is carried out in the presence of atleast one, preferably one, bulky nitrogen base.

[0099] Bulky nitrogen bases are, for example, amines of the generalformula

NR⁸R⁹R¹⁰  (VII)

[0100] where R⁸, R⁹ and R¹⁰ are each, independently of one another,C₁-C₂₀-alkyl, C₅-C₁₄-aryl or C₆-C₁₅-arylalkyl or two or three of theradicals R⁸, R⁹ and R¹⁰ together with the nitrogen atom may form amonocyclic, bicyclic or tricyclic heterocycle having from 4 to 8 carbonatoms per ring,

[0101] with the proviso that one, two or three of the radicals R⁸, R⁹and R¹⁰, preferably two or three, are each, independently of oneanother, either bound to the nitrogen atom via a tertiary or quaternarySp³ carbon atom or are an aryl radical which is monosubstituted ordisubstituted, preferably disubstituted, in the ortho positions.

[0102] Radicals which may be bound to the nitrogen atom via a tertiaryor quaternary Sp³ carbon atom are, by way of example and preferably,isopropyl, isobutyl, tert-butyl, 1-methylbutyl, 1-ethylpropyl, 1,1-10dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 1,1-dimethylbutyl,1,2-dimethylbutyl, 1,3-dimethylbutyl, 1-ethylbutyl,1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl,cyclopentyl, cyclohexyl and cycloheptyl.

[0103] Aryl radicals which are monosubstituted or disubstituted in theortho positions are, for example, o-tolyl, 2,6-dimethylphenyl,2-ethyl-6-methylphenyl, 2,6-diisopropylphenyl, o-anisyl and2,6-dimethoxyphenyl.

[0104] For the purposes of the invention, monocyclic heterocycles are,for example, N-methyl-2,2,6,6-tetramethylpiperidine andN-methyl-2,5-dimethylpyrrolidine.

[0105] Further bulky nitrogen bases are N-heteroaromatic compounds whichare substituted in both the ortho positions relative to the nitrogen.

[0106] These are preferably 2,6-disubstituted pyridines such as2,6-lutidine, 2,6-diethylpyridine, 2,6-diisopropylpyridine,2,6-dimethoxypyridine, 2,6-di-tert-butylpyridine.

[0107] In the process of the invention, bulky nitrogen bases used arevery particularly preferably ethyldiisopropylamine, triisopropylamine,diisopropylaniline, triisobutylamine, ethyldiisobutylamine,dicyclohexylmethylamine, dicyclohexylethylamine, cyclohexyldiethylamine,cyclohexyldimethylamine and 2,6-bis-diisopropylpyridine, among whichdicyclohexylmethylamine, dicyclohexylethylamine,cyclohexyldimethylamine, cyclohexyldimethylamine are very particularlypreferred.

[0108] The molar amount of base used can be, for example, from 0.5 to100 times, preferably from 1.0 to 10 times, particularly preferably from1.0 to 1.5 times and very particularly preferably from 1.0 to 1.2 times,the molar amount of X to be replaced in the general formula (I).

[0109] In an embodiment of the process of the invention, the bulkynitrogen base can be used in combination with another base. In thiscase, for example, from 1 to 95% of the amount of bulky nitrogen basecan be replaced by a nonbulky nitrogen base.

[0110] Nonbulky nitrogen bases for the purposes of the invention are,for example, alkali metal and alkaline earth metal carboxylates such asacetates, propionates, benzoates, alkali metal and alkaline earth metalcarbonates, hydrogencarbonates, phosphates, hydrogenphosphates,hydroxides. Alkali metals are preferably lithium, sodium, potassium andcaesium, alkaline earth metals are preferably calcium, magnesium andbarium.

[0111] As olefins which bear at least one hydrogen atom on the doublebond, it is possible to use, for example, those of the general formula(VIII),

R¹¹ CH═C¹²R¹³ (VII)

[0112] where, independently of one another,

[0113] R¹¹ is hydrogen or methyl and

[0114] R¹² is hydrogen or methyl and

[0115] R¹³ can be hydrogen, cyano, SO₃M, C₁-C₈-alkyl, a carbocyclicaromatic radical having from 6 to 18 framework carbon atoms or aheteroaromatic radical having from 5 to 18 framework carbon atoms inwhich no, one, two or three framework carbon atoms per ring, but atleast one framework carbon atom in the total molecule, may be replacedby heteroatoms selected from the group consisting of nitrogen, sulphurand oxygen

[0116] or a radical of the general formula (IX)

[0117] where

[0118] G is OM, OH, NH₂, OR 14, NHR¹⁴ or N(R¹⁴)², and R¹⁴ isC₁-C₁₂-alkyl, C₆-C₁₅-arylalkyl or C₅-C₁₄-aryl or

[0119] the N(R¹⁴)₂ moiety is a cyclic amino radical such as morpholino,pyrrolidino or piperidino, and M can be an alkali metal ion, half anequivalent of an alkaline earth metal ion, an ammonium ion or an organicammonium ion.

[0120] The carbocyclic aromatic radicals and heteroaromatic radicals canbe substituted in the same way as described under the aromatic compoundsof the general formula (I).

[0121] Preferred examples of olefins of the general formula (X) areethene, propene, butene, 1,1,1-trifluoro-2-propene, substituted orunsubstituted vinyl-C₆-C₁₀-aromatics such as styrene or the isomericvinylnaphthalenes, 2-, 3- or 4-fluorostyrene, 2-, 3- or 4-chlorostyrene,2-, 3- or 4-bromostyrene, 2-, 3- or 4-iodostyrene, 2-, 3- or4-cyanostyrene, 2-, 3- or 4-(C₁-C₁₂)-alkoxystyrene such as 2-, 3- or4-methoxystyrene, 2-, 3- or 4-nitrostyrene, 2-, 3- or4-styrenecarboxylic acid, C₁-C₁₂-alkyl 2-, 3- or 4-styrenecarboxylatessuch as methyl 2-, 3- or 4-styrenecarboxylate, C₆-C₁₂-aryl 2-, 3- or4-styrenecarboxylates such as phenyl 2-, 3- or 4-styrenecarboxylate, 2-,3- or 4-styrenesulphonic acid or their salts, 3- or 4-vinylphthalicacid, di-C₁-C₁₂-alkyl 3- or 4-vinylphthalates such as dimethyl 3- or4-vinylphthalate, di-C₆-C₁₀-aryl 3- or 4-vinylphthalates such asdiphenyl 3- or 4-vinylphthalate, 3- or 4-vinylphthalic anhydride,vinylhetaryls such as N-vinylimidazole or 2- or 4-vinylpyridine, alsoacrylonitrile, acrylic acid, C₁-C₁₂-alkyl acrylates such as methylacrylate, ethyl acrylate, n-propyl acrylate, 2-ethylhexyl acrylate,acrylamide, vinylsulphonic acid and its sulphonates and acrylamide.

[0122] As olefins having at least one hydrogen substituent, veryparticular preference is given to ethylene, propene, acrylonitrile,acrylic acid, methyl acrylate, 2-ethylhexyl acrylate, acrylamide,1,1,1-trifluoro-2-propene and styrene, with especial preference beinggiven to acrylonitrile, methyl acrylate, acrylamide and styrene andgreatest preference being given to acrylamide.

[0123] The amount of olefin used can be, for example, from 0.2 to 200times (when used as solvent) the molar amount of the aromatic compoundof the general formula (I); from 0.5 to 5 times is preferred and from0.8 to 1.2 times is very particularly preferred. Even greater preferenceis given to 0.9 to 1.0 times.

[0124] If aromatic compounds of the general formula (I) or olefins ofthe general formula (VIII) which bear a free acid group such as asulphonic acid or carboxylic acid group, the amount of base used, viz. abulky nitrogen base or nonbulky nitrogen base, has to be increasedcorrespondingly.

[0125] The process of the invention is carried out in the presence of adipolar aprotic solvent.

[0126] Preferred dipolar aprotic solvents are amide solvents such asdimethylformamide, dimethylacetamide, N-methylpyrrolidone orN-methylcaprolactam;

[0127] sulphoxides and sulphones such as dimethyl sulphoxide ortetramethylene sulphone (sulpholane) or mixtures of such solvents;

[0128] nitriles such as acetonitrile, benzonitrile and benzyl nitrile,ketones such as dimethyl ketone, diethyl ketone, methyl tert-butylketone.

[0129] Dimethylformamide, dimethylacetamide and N-methylpyrrolidone areparticularly preferred.

[0130] Dimethylacetamide is very particularly preferred.

[0131] The amount of any solvent used can be, for example, from 50 ml to5000 ml, preferably from 100 to 500 ml, per mol of the aromatic compoundof the general formula (I).

[0132] The reaction temperature can be, for example, from 20° C. to 200°C., preferably from 80 to 150° C. and particularly preferably from 0° C.to 120° C.

[0133] The reaction can be carried out at, for example, from 0.2 to 100bar; preference is given to atmospheric pressure.

[0134] The reaction time can be, for example, from 0.2 hour to 72 hours;preference is given to from 1 to 36 hours.

[0135] The reaction is preferably carried out under a protective gasatmosphere with substantial exclusion of oxygen and moisture. Possibleprotected gases are, for example, nitrogen and noble gases such as argonor mixtures of such gases.

[0136] In a preferred embodiment of the process of the invention, thearomatic compound of the general formula (I) together with the olefin,the base, the palladium compound and the ligand are placed in a reactionvessel under protective gas and the mixture is heated to the reactiontemperature while stirring. After the reaction is complete, the mixtureis poured into water. Solid products then precipitate and can befiltered off with suction and, for example, washed with water. Liquidproducts can be extracted by means of an organic solvent which isimmiscible or sparingly miscible with water and be worked up, forexample, by distillation.

[0137] Solid products can, if appropriate, be purified further by, forexample, recrystallization or reprecipitation.

[0138] As an alternative, it is also possible for the aromatic compoundof the general formula (I) together with the olefin, the base and theligand to be placed in a reaction vessel and the palladium compound tobe added.

[0139] Furthermore, it is also possible for the aromatic compound of thegeneral formula (I) together with the base, the ligand and the palladiumcompound to be placed in a reaction vessel and the olefin to be added.

[0140] Furthermore, it is also possible for the olefin together with thebase, the ligand and the palladium compound to be placed in a reactionvessel and the aromatic compound of the general formula (I) to be added.

[0141] Furthermore, it is also possible for the base, the ligand and thearomatic compound of the general formula (I) to be placed in a reactionvessel and the palladium compound to be added.

[0142] In each of the possible methods of addition mentioned above, theligand can also be added together with the palladium compound.

[0143] It is advantageous to use a weakly acidic aqueous solution duringthe work-up to bind any remaining base as salt. The base can, forexample, be recovered by alkalisation and extraction of the washingliquid with an organic solvent.

[0144] The process of the invention gives arylolefins of the generalformula (X)

Ar—(R¹¹C═CR¹²R¹³)_(n)  (X)

[0145] where

[0146] Ar and n are as defined under the general formula (I) and R¹¹,R¹², R¹³ are as defined under the general formula (VIII).

[0147] The process of the invention is particularly useful for preparingarylacrylic acid derivatives of the general formula (XI)

Ar—(R¹¹═R¹²R¹³)  (XI)

[0148] where

[0149] Ar is as defined under the general formula (I) and R¹¹, R¹² areas defined under the general formula (X) and R¹³ is cyano or a radicalof the general formula (XI) with the meanings specified there.

[0150] The advantages of the process of the invention are the ease withwhich it can be carried out and the high yields of aromatic olefins.Furthermore, high catalyst turnover numbers (TONs) of far above 100 molof haloaromatic/mol of palladium catalyst are achieved.

[0151] The invention is further illustrated but is not intended to belimited by the following examples in which all parts and percentages areby weight unless otherwise specified.

EXAMPLES Examples 1-9

[0152] 0.4 ml of 4-chlorobenzotrifluoride, 0.178 g of acrylamide, 1.4 mg(0.24 mol %) of palladium acetate and 4.8 mg ofphenyldi(t-butyl)-phosphine and 2 ml of dimethylacetamide are placed ina Schlenk vessel. The indicated amount of the specified base is in eachcase added to this initial charge and the mixture is heated to 130° C.under protective gas. After 4 hours, samples are taken and analysed byHPLC. Weight Example used Yield number Base [g] [%] 1 (comparison)Na₂CO₃ 0.382 0 2 (comparison) Triethylamine 0.364 6.4 3 (comparison)Diazabicyclooctane 0.404 15.4 4 (comparison) Diazabicycloundecane 0.5480 5 Ethyldiisopropylamine 0.465 35.4 6 Dicyclohexylmethylamine 0.703 >997 Dicyclohexylethylamine 0.754 83 8 Cyclohexyldiethylamine 0.559 >99 9Cyclohexyldimethylamine 0.458 >99

Example 10

[0153] 0.40 ml of 4-chlorobenzotrifluoride, 0.178 g of acrylamide, 0.7mg of palladium acetate (0.12 mol %), 2.7 mg ofdi(tert-butyl)phenylphosphine and 3 ml of dimethylacetamide are placedin a Schlenk vessel. 0.559 g of cyclohexyldiethylamine is added to thisinitial charge, and the mixture is then heated to 120° C. underprotective gas. After 5.5 hours, a sample is taken and analysed by HPLC.84% conversion to the desired product (TON=700, TOF=127 h⁻¹).

Examples 11 and 12

[0154] In each case in a Schlenk vessel, 237.6 mg of acrylamide, 0.50 mlof 4-chlorobenzotrifluoride, 0.87 ml of dicyclohexylmethylamine, 4.2 mgof palladium acetate, 16.5 mg of di(tert-butyl)phenylphosphine and 100mg of 1,3,5-trimethoxybenzene as internal standard are dissolved once in3 ml of dimethylacetamide (Example 11) and once in 3 ml of dioxane(Example 12). The vessels are then placed in the same oil bath at 100°C. and samples for HPLC are taken at regular intervals. The results wereused to produce a time-conversion table. Conversion in Conversion in % %Time [h] (Example 11) (Example 12) 0 0 0 0.5 1.3 2.3 1 8.3 3.7 1.5 11.45.8 2 15.2 8.4 2.5 20.2 8.4 4 30.1 14.5

[0155] Time-conversion table comparing the solvents dimethylacetamide(Example 11) and 1,4-dioxane (Example 12).

Examples 13 and 14

[0156] In each case in a Schlenk vessel, 237.6 mg of acrylamide, 0.50 ml(3.71 mmol) of 4-chlorobenzotrifluoride, 0.87 ml ofdicyclohexylmethylamine, 0.8 mg (0.11 mol %) of palladium acetate, 3.3mg of di(tert-butyl)phenylphosphine and 100 mg of1,3,5-trimethoxybenzene as internal standard are dissolved once in 4 mlof dimethylacetamide (Example 13) and once in 4 ml of dioxane (Example14). Both tubes are then placed in the same oil bath at 130° C. (themixture containing dioxane in a pressure tube) and stirred for 3 hours.A sample is taken in each case before the reaction and after the end ofthe reaction and the conversion is calculated from HPLC analysis of thesamples. In dimethylacetamide (Example 13), 33% conversion (TON=298,TOF=99 h⁻¹) was achieved after 3 hours, while in dioxane (Example 14),the conversion was only 2.4%.

Examples 15 and 16

[0157] In each case in a Schlenk vessel, 237.6 mg (3.34 mmol) ofacrylamide, 0.50 ml (3.71 mmol) of 4-chlorobenzotrifluoride, 0.87 ml(4.08 mmol) of dicyclohexylmethylamine, 0.8 mg (3.7 μmol) of palladiumacetate, 3.0 mg (14.9 μmol) of tri(tert-butyl)phosphine and 100 mg of1,3,5-trimethoxybenzene as internal standard are dissolved once in 4 mlof dimethylacetamide (Example 15) and once in 4 ml of dioxane (Example16). Both tubes are then placed in the same oil bath at 130° C. (themixture containing dioxane in a pressure tube) and stirred for 3 hours.A sample is taken in each case before the reaction and after the end ofthe reaction and the conversion is calculated from HPLC analysis of thesamples. In dimethylacetamide (Example 15), 52% conversion (TON=469,TOF=156 h⁻¹) was achieved after 3 hours, while in dioxane (Example 16),there was no conversion.

[0158] Although the invention has been described in detail in theforegoing for the purpose of illustration, it is to be understood thatsuch detail is solely for that purpose and that variations can be madetherein by those skilled in the art without departing from the spiritand scope of the invention except as it may be limited by the claims.

What is claimed is:
 1. Process for preparing arylolefins, comprisingreacting aromatic compounds of the general formula (I), Ar—[X]_(n)  (I),where n is one or two and Ar is a substituted or unsubstituted aromaticradical and X are each, independently of one another, chlorine, bromine,iodine or a sulphonate, with olefins which bear at least one hydrogenatom on the double bond in the presence of a palladium catalyst, atleast one bulky nitrogen base and in the presence of a dipolar aproticsolvent.
 2. Process according to claim 1, wherein the dipolar aproticsolvents used are amide solvents, sulphoxides, nitriles, ketones orsulpholanes or mixtures thereof.
 3. Process according to claim 1,wherein the dipolar aprotic solvents used are dimethylformamide,dimethylacetamide, N-methylpyrrolidone or mixtures thereof.
 4. Processaccording to claim 1, wherein the general formula (I), Ar is acarbocyclic aromatic radical having from 6 to 24 framework carbon atomsor a heteroaromatic radical having from 5 to 24 framework carbon atomsin which no, one, two or three framework carbon atoms per ring, but atleast one framework carbon atom in the total molecule, is/are replacedby heteroatoms selected from the group consisting of nitrogen, sulphurand oxygen, where the carbocyclic aromatic radical or heteroaromaticradical is substituted by up to five identical or different substituentsper ring selected from the group consisting of hydroxy, fluoro, nitro,cyano, free or protected formyl, C₁-C₁₂-alkyl, C₅-C₁₄-aryl,C₆-C₁₅-arylalkyl, —PO—[(C₁-C₈)-alkyl]₂, —PO—[(C₅-C₁₄)-aryl]₂,—PO—[(C₁-C₈)-alkyl)(C₅-C₁₄)-aryl)], tri(C₁-C₈-alkyl)siloxyl and radicalsof the general formula (II), A-B-D-E (II) where, independently of oneanother, A is absent or is a C₁-C₈-alkylene radical and B is absent oris oxygen, sulphur or NR¹, where R¹ is hydrogen, C₁-C₈-alkyl,C₆-C₁₅-arylalkyl or C₅-C₁₄-aryl and D is a carbonyl group and E is R²,OR², NHR³ or N(R³)₂, where R² is C₁-C₈-alkyl, C₆-C₁₅-arylalkyl,C₁-C₈-haloalkyl or C₅-C₁₄-aryl and R³ are each, independently of oneanother, C₁-C₈-alkyl, C₆-C₁₅-arylalkyl or C₆-C₁₄-aryl or the moietyN(R³)₂ is a cyclic amino radical, and radicals of the general formulae(IIIa-e) A-E  (IIIa) A-SO₂-E  (IIIb) A-B-SO₂R²  (IIIc) A-SO₃W  (IIId)A-COW  (IIIe) where A, B, E and R² are as defined above and W is OH,NH₂, or OM, where M is an alkali metal ion, half an equivalent of analkaline earth metal ion, an ammonium ion or an organic ammonium ion andX is chlorine, bromine, iodine, trifluoromethanesulphonyloxy ornonafluorobutanesulphonyloxy.
 5. Process according to claim 1, whereinthe palladium catalysts used are palladium complexes.
 6. Processaccording to claim 1, wherein the palladium catalysts used are palladiumcomplexes which are generated in the reaction solution from palladiumcompounds and phosphorus compounds.
 7. Process according to claim 6,wherein the phosphorus compounds used are monophosphorus compounds ofthe general formula (Va), P(E-R⁴)₃  (Va) where E are each, independentlyof one another and independently of R⁴, absent or oxygen and theradicals R⁴ are each, independently of one another, C₁-C₈-alkyl orunsubstituted phenyl, naphthyl or ferrocenyl or phenyl, naphthyl orferrocenyl substituted by one, two or three radicals R⁵, where R⁵ isC₁-C₈-alkyl, C₁-C₈-alkoxy, chlorine, fluorine, N(C₁-C₆-alkyl)₂,CO₂-(C₁-C₆-alkyl), —CON(C₁-C₆-alkyl)₂, cyano or CO(C₁-C₆-alkyl) ordiphosphorus compounds of the general formula (Vb),(R⁶-E)₂P-E-Z-E-P(E-R⁶)2 (Vb) where E are each, independently of oneanother and independently of R⁶ and Z, absent or oxygen and the radicalsR⁶ are each, independently of one another, C₁-C₈-alkyl or phenyl,naphthyl or heteroaryl having from 5 to 12 framework carbon atoms whichmay be unsubstituted or substituted by one, two or three radicals R⁷,where R⁷ are selected independently from the group consisting ofC₁-C₈-alkyl, C₁-C₈-alkoxy, fluorine and cyano and Z is an unsubstitutedor substituted radical selected from the group consisting ofC₁-C₄-alkylene, 1,2-phenylene, 1,3-phenylene, 1,2-cyclohexylene,1,1′-ferrocenylene, 1,2-ferrocenylene, 2,2′-(1,1′-binaphthylene) and1,1′-biphenylene.
 8. Process according to claim 6, wherein thephosphorus compounds used are tri(tert-butyl)phosphine,phenyldi(tert-butyl)phosphine and ferrocenyldi(tert-butyl)phosphine. 9.Process according to claim 6, wherein the molar ratio of phosphorus topalladium in the reaction mixture is from 1:1 to 100:1.
 10. Processaccording to claim 1, wherein the molar ratio of X in compounds of thegeneral formula (I) to palladium is from 10 to 20
 000. 11. Processaccording to claim 1, wherein the bulky nitrogen bases used are aminesof the general formula, NR⁸ R⁹R¹⁰  (VII) where R⁸, R⁹ and R¹⁰ are each,independently of one another, C₁-C₂₀-alkyl, C₅-C₁ 4-aryl orC₆-C₁₅-arylalkyl or two or three of the radicals R⁸, R⁹ and R¹⁰ togetherwith the nitrogen atom may form a monocyclic, bicyclic or tricyclicheterocycle having from 4 to 8 carbon atoms per ring, with the provisothat one, two or three of the radicals R⁸, R⁹ and R¹⁰, are each,independently of one another, either bound to the nitrogen atom via atertiary or quaternary Sp³ carbon atom or are an aryl radical which ismonosubstituted or disubstituted in the ortho positions orN-heteroaromatic compounds which are substituted in the two orthopositions relative to the nitrogen.
 12. Process according to claim 1,wherein the bulky nitrogen bases used are dicyclohexylmethylamine,dicyclohexylethylamine, cyclohexyldiethylamine andcyclohexyldimethylamine.
 13. Process according to claim 1, wherein theolefins bearing at least one hydrogen atom on the double bond areolefins of the general formula (X), R¹¹CH═CR¹²R¹³  (X) where,independently of one another, R¹¹ is hydrogen or methyl and R¹² ishydrogen or methyl and R¹³ is hydrogen, cyano, SO₃M, C₁-C₈-alkyl, acarbocyclic aromatic radical having from 6 to 18 framework carbon atomsor a heteroaromatic radical having from 5 to 18 framework carbon atomsin which no, one, two or three framework carbon atoms per ring, but atleast one framework carbon atom in the total molecule, may be replacedby heteroatoms selected from the group consisting of nitrogen, sulphurand oxygen or a radical of the general formula (XI)

where G is OM, OH, NH₂, OR¹¹, NHR¹⁴ or N(R¹⁴)₂, and R¹⁴ is C₁-C₁₂-alkyl,C₆-C₁₅-arylalkyl or C₆-C₁₀-aryl or the N(R¹⁴)₂ and M is an alkali metalion, half an equivalent of an alkaline earth metal ion, an ammonium ionor an organic ammonium ion is a cyclic amino radical
 14. Processaccording to claim 1, wherein the reaction temperature is from 20° C. to200° C.
 15. A method of preparing medicaments or agrochemicalscomprising incorporating arylolefins which have been prepared accordingto claim
 1. 16. A method of preparing light protection agents comprisingincorporating arylacrylic acid derivatives which have been preparedaccording to claim 1.